Light eeflectoe



March A. S. CRANDALL LIGHT REFLECTOR Filed March 11, 1926 Patented Mar.15, 1927.

UNITED STATES ARVID S. CRANDALL, OF CHICAGO, ILLINOIS.

LIGHT REFLECTOR.

Application filed March 11, 1926. Serial No. 93,835.

This invention relates to light reflectors and its principal object isto obtain a more effective and uniform distribution of the light raysissuing from a lamp, to obtain r a more uniform degree of illuminationwithin the zone to be illuminated, and to distribute the light withuniform intensity, on adja cent and more remotely located surfaces.

'With most, if not all of the reflectors now in common use instage-lighting systems, sign illuminating devices, show caseilluminating devices and the like, an unnecessary number of lamps isrequired, or higher powered lamps are required, to obtain the desiredeffect. One object of the present invention is to obtain'more effectiveresults by the use of a less number of lamps and with the expenditure ofless current than has heretofore been required. Another object is toprovide a reflector of novel form, capable of reflecting and diffusingthe light rays in such manner that all of the area within the light zoneof the lamp may be illuminated at practically the same intensity, andwithout the overlapping of bright and dull areas. Vith these and otherobjects and advantages in view, this invention vconsists in the severalnovel features hereinafter fully set forth and claimed.

The invention is clearly illustrated in the accompanying drawing, inwhich:

Fig; l is a Vertical cross section taken through a fragment of a stageor other structure containing a dome, and showing a lamp containing oneof the reflectors forming the subject matter of this specification, inplace therein; Fig. 2 shows the device in use at the foot light sectionof a stage, the view being a vertical cross section; Fig. 3 is a detail,vertical cross section of the device; Fig. 4 is a plan of one lamp andfragments of two adjacent lamps; and Fig. 5 is a detail vertical,longitudinal section taken on line 5-5 in Fig. at.

Referring to said drawing, the reference character 6 designates thecasing of the device, which as a preference, comprises front and backwalls 7 8, a bottom wall 9 and side walls 10. The bottom wall 9 may havea hinged door 11 through which the interior of the case is renderedaccessible. The top of the casing is open and is covered by a glass orother transparent plate or slide 12, which may be of any desired color.In obtaining curtain stage lighting effects, a number of lampscontaining the invention are placed side by side, as shown in Fig. 4,and glass plates of the same color may be placed in the alternate lamps,or the lamps may be arranged in groups, one lamp in each group having aglass plate of a certain color, and the lamps with glass plates of thesame color following in a regular sequence. Preferably the inner facesof the side walls 10 are in the nature of light reflecting surfaceswhereby light rays are reflected in a sidewise direction. The top of thelamp casing inclines upwardly from front to back and has a grooved edgeportion 13 in which the glass plate is held. A button 14 pivotallysecured on the front wall 7 engages with the front edge of the glassplate and retains it in place in the groove.

Secured to the inner side of the casing is a bracket 15 which supportsthe socket 16 of an electric incandescent lamp 17 of desirable designand wattage for the purpose intended. A lug 18 is secured to the outerside of the bottom of the casing and is pivotally secured to asupporting post or bracket 19 whereby the lamp may be tilted to stand atany angle desired. Vent openings 20 are provided in the casing for theescape of heated air.

Vithin the lamp casing is the reflector A, forming the subject matter ofthis specification. It is shown as composed of corrugated material, thecorrugations being rounded and running from side to side of the case.The reflector comprises two curved, tough like sections 01,, b, joinedat the place lettered c, the portion a, being substantiallysemi-circular or being parabolical in form and defined by the edges 0,(Z, and the curved section 6 being approx? mately a fourth of a circleor paraholical .in form and extending from the edge 0 to the placelettered e, where the curve merges into a straight part 7', running tothe top of the casing where its edge g defines its upper end.

The light center it of the electric lamp is preferably located adjacentthe middle of the curved section a, and some of the direct light raysissuing from the electric lamp, 1?, pass out through that part of theglass plate, 12 contained between the edges d, y. Other light raysissuing from the electric lamp strike the curved section a of thereflector, and some are reflected out through the glass plate 12, andsome are reflected upon the curved section b, and others upon straightloo part f, all being eventually, reflected out through the glass plate12. It. Will beobserved, therefore, that both direct and reflected lightrays are sent out frointhe elec, tric lamp, and distributed in suchmanner that all of the illuminated area receives-.substantially the samedegree of illumination in respective of its distance. away from thelamp. By reason of the corrugated reflecting surface, the light rays arebroken up andscattered overthe-surface to be illuminated.

In Figs. 1; 2 and El-the l-ightzone illuminated by the direct light raysis included in the angle formed by the dotted lines a, a, and thatillun'rinate'd by the reflected light rays is included-in the angleformed by the dotted lines ('1, I). These angles may vary, however, onaccount of the corrugations and precise location of the light centre.

Referring now more particularly to Fig. 1, which shows the lamp used forthe purpose of illuminating an upright-back ground wall or the like ll,and a dome or ceiling B The lamps may contain glass plates ofthe desiredcolors and are usually arranged-in-a row and placed in a trough ordepressed place 6, whereby all of thewall and'd'ome may be visibleabove. a floor line 6 It will be observed that the direct and somereflected light rays are directed in a direction, extending generallyupwards, and include the upper portion of the wall'B and the dome P1Some of the light rays reflected by the curved section a, of thereflector pass upward and some pass to the curved and straight parts 6,f, ofthe reflector, from which they are reflected back to the lowerpartof the wall B. Some of the light rays from the electric lamp strikethe curve'd and straight parts. I), f, of-the reflector and arereflected'back against the lower half'of the wall B. It will be seen,therefore, that the entire surface withinthe light zone of the lamp isilluminated in an even manner throughout, and that there are no darkplaces visible on the illun'iina-ted surface. A wall and dome ofithiskind is often used at the back of theatrical stages where it isespecially desirous of evenly illuminating the entire surface. Inasmuchas the inner sides 10 of'the lamp casing act as reflecting surfaces,light rays are reflected from each side surface and intermingle withlight rays re 'lected from adjacent lamps, thus affording a wide rangeof light beams in atransverse or lateral direction.- The result is thatthe colored'light from one lamp diffuses into the colored light fromadjacentlamps, and a beautiful and uniform lighting effect is created. 1

In Fig. 2 the lamp is shown in use as a foot light. Here also thatportion of the stage which derivesits light from the foot lights isevenly lighted. Persons and other objects coming within the light zoneof the lamps receive a uniform.distribution of the light whereby all:parts thereof arerevenly illuminated. The use of the reflector is notlimited to the, situations mentioned, but it may be used in anysituation Where an even, uniform,distribution of light is required onadjacent and more remote places.

Moreor less variation of the exact de tails of construction is possibleWithout departing from the spirit of this invention; 1 desire,therefore, not to limit myself to the exact form of the constructionshown and described, but intend, in the foil-o ing claims, to point-outall of the invention disclosed herein.

1 claim as new and desire to secure by Letters Patent:

l. 1 1' light reflector having two concave, curved, light reflectingfaces, the concavity of one face being relatively deepand the curved-endof one face joining acurved end ofthe other, and one of saidcurved facesmerging into a substantially straight face, the opposite ends of saidlight reflecting faces being spaced apart to provi le an openingfor thepassage of direct and reflected light rays issuing from a light sourcelocz'rtedin th-e deep concave space of the reflector, said openingextending transversely of'the plane of the substantially straight lightreflecting face whereby light rays reflected bysaid substantiallystraight light reflecting face cross the direct light rays issuing fromsaid opening in transverse lines.

2. A light reflector comprising two concave, curved and-corrugated lightreflecting sections, tlreconcavity of one section being relatively deepand a curved end of one section joining a curved end of the other, andone of curved sections merging into a substantially straight part, theother ends of said two sections being spaced apartto provide an openingforthe passage of direct and. reflected light rays issuing from a lightsource located in the deep concave section of-the reflector, the deepcurved section being arranged toreflect light rays to the other section,and said other section being arranged to reflect light rays out throughsaid opening along lines transverse, with-re spect=to the generaldirection taken by the direct light rays passing from said lamp andthrough said opening.

A light reflector comprising a.curved, relatively deep, trough likesection, and a second curved, relatively shallow, trough like section,having a partimerging into an approximately straight portion,v the twosections. being arranged side by side in such manner that light rays arereflected from the first mentioned section to the curved andapproximatelystraight parts of the second named section, and bothsections being adapted to receive direct light rays from a common lightsource located in the deep seetion, there being an opening through whichlight issues from said reflector extending transversely of said straightlight reflecting portion whereby light rays reflected by said straightlight reflecting portion are directed transversely of the direct lightrays passing through said opening.

4-. A light reflector comprising a curved, relatively deep, trough likelengthwise corrugated section, and a second curved, trough likelengthwise corrugated section, having a part merging into anapproximately straight portion, the two sections being arranged side byside in such manner that light rays are reflected from the deep sectionto the curved and approximately straight parts of the second namedsection, and both sections being adapted to receive direct light raysfrom a common light source located in the deep section, there being anopening through which light issues from said reflector extendingtransversely of said straight light reflecting portion whereby lightrays reflected by said straight light reflecting portion are directedtransversely of the direct light rays passing through said opening.

5. A light reflector comprising two spaced sides, the upper edges ofwhich incline upwardly from front to back, a curved, trough likereflector section extending between said sides at the front portionthereof, a second curved, trough like section, extending be tween saidsides at the rear thereof and having an approximately straight partextending to the top of the sides.

ARVID S. GRANDALL.

